Calvin Hsia's WebLog

A colleague asked the other day if the CLR releases memory when it’s no longer needed. Suppose you allocate lots of memory, then release it. The CLR will grow the managed heap (the green below), but it will also shrink it if it can. All memory in a process...

I showed my 9 year old son a cool drawing program called Physamajig , in which users can draw objects, which behave like real physical objects, including reacting to gravity, friction, and bounce. He was having fun with it on my Surface RT and it reminded...

  Sometimes when you use Visual Studio, or any application on a computer, there’s a notable pause when you try to do something. For example, trying to access a file on a network share somewhere, perhaps on a slow connection, the application will...

This month marks the 20 th anniversary of the Microsoft MVP program, so MVPs were in the news. Apparently I had a lot to do with the founding of the program J Wikipedia: http://en.wikipedia.org/wiki/Microsoft_Most_Valuable_Professional Microsoft News...

Sometimes applications fail. If you are the author and it fails on your machine, typically you fire up the code in a debugger, figure out the issue, fix it, and rebuild the code. If the applications is out in the wild, perhaps with millions of users,...

  I was creating a project that’s a Windows Service, which has components running in multiple processes, using multiple threads and named pipes for communication. To understand the behavior of the code, I wanted to have accurate logging that: · The...

It’s great to be able to write tests and execute them while developing a project. While I’m developing, I can hit a button and run the dozens of tests to see if I’ve broken anything. As code gets written lots of things get refactored, moved around, etc...

Sometimes you want to have very fine control of how your application looks and behaves. Other times, you just want to draw something on your UI. It’s pretty easy to create your own control class and put instances of it on your form. The sample below create...

One of the performance improvements we made in .Net was with System.Text.StringBuilder . StringBuilder is used in lots of code to build strings: it has various methods to modify strings quickly. Once a string is built, the ToString method is called to...

There is a comment on this Visual Studio Blog post (about how we made Visual Studio faster): “Focus on speed, not memory usage. Memory is very cheap, but CPU performance is muuuuuuuuch moooooooore expensive.” Yes, memory keeps getting cheaper, but actually...

Suppose you wrote some C# code like this: var str1 = "ThisIsAString" ; var str2 = "ThisIsAnotherString" ; As you’d expect, each string is stored in the resulting built binary and also in memory when the binary is loaded,...

    I love having test projects included in my solutions. Software is alive. I’m constantly making improvements/changes/fixes. When I have customers asking for various features in my code, or for code improvements, being agile and able to publish...

When you hear about threads and threading, you hear that they allow concurrent execution of code, which is supposed to lead to better performance. Most computers nowadays have more than one CPU, meaning that each CPU can be executing code at the same...

A long time ago I worked in the Green Building (building 54 at MIT) .   Several NASA Apollo lunar missions (I think 11, 12, 14… I know it wasn’t 13 J ) placed seismometers on the moon, in various locations. They didn’t detect earth quakes. The Moonquakes...

  Sometimes your program wakes up and finds itself running in an environment that might not be as suitable as you’d like.   For example, it might be distributed to a user running on a machine with not enough memory, and could be failing. Perhaps...

  I have some code that attaches and injects code into a target application (like Visual Studio or IE) to examine its memory use. In order to do that, my code freezes the target.   I wanted my application to respond to WM_QUERYENDSESSION so...

  Here’s a pattern of code use I’ve seen in a few places. There’s a function DeserializeList that returns an array of various sizes, depending on the input. This code can be called to deserialize (rehydrate) an object from a stream. For example,...

Last time ( Improve your managed debugging skills: examining registers and memory ) we examined some debugging techniques to understand the behavior of managed code. It might take a long time or many manual steps to reproduce a particular software...

  I was helping a colleague and we were deep in the middle of a debug session, single stepping some code and we wanted to see a value in the debugger. The debugger showed either nothing, because the intermediate value has been optimized out, or a...

The sounds that we hear can be recorded via a microphone and can be graphed as a signal of amplitude versus time. Low notes show as a lower frequency wave, and high notes show as higher frequency waves. Over the past few decades, some music players, like...

  As you know, a treeview control is very useful for viewing hierarchical information. Each node in a tree can have its own parent/child relationships.   Some of these trees can be extremely large, and can thus be prohibitively expensive to...

  Last month   in   Dynamically create huge tooltips in WPF TreeView and ListView I showed some code that creates large tooltips to present lots of data.   Today, we’ll talk about creating automatic tests for this feature.   Testing...

  Tooltips are useful. When the mouse hovers over a button a tip can indicate what happens when it’s clicked. The mouse move does not actually invoke the button, but can give information in a passive way.   Sometimes I want to make huge tooltips...

Sometimes you need to write a method that requires recursion to be elegant. Often that method needs to accumulate data between recursion levels There are many ways to do so, and some are more elegant than others. I like the Optional Parameter method...

In the old days (about 16 years ago), FoxPro’s object, containership and inheritance models made it easy to put objects inside other objects. So, for example, a FoxPro grid of Customers could have a column containing a grid of each customer’s orders,...